I'm reading Digital Fortress, by Dan Brown, and as usual he likes to intersperse his storytelling with foreign sentences and expressions. The problem is that many times he doesn't get it right. Here are a few examples (the expression in parentheses is the explanation he gives in English):

Sí, sí, señor. My name is Señor Roldán. - Nobody would introduce himself as Señor Roldán, since señor is not found in anybody's birth certificate. Señor would be used when talking to or about a man to whom respect must be shown.

In German:

Du hast einen Ring (you have a ring) - Theoretically there's nothing wrong with Du hast einen Ring, but here Sie would have been more appropriate, Sie haben einen Ring, since the main character in the book doesn't know the German with whom he comes in contact.